Currently, Li-ion batteries have been applied in green vehicles, such as electric vehicles (EVs) and hybrid electric vehicles (HEVs). The workable voltage of a single cell in a Li-ion battery is approximately 3-4 volts, but EVs and HEVs usually require higher voltages up to more than 100 volts. Usually, multiple cells are coupled to each other in series to drive EVs and HEVs.
In battery management, the status of the cells, such as cell voltage, cell temperature and cell current, is measured and sent to an analog-to-digital converter (ADC) by a plurality of analog channels. Usually, offset cancellation is done to improve the accuracy of the ADC. However, when an abnormal condition occurs in the analog channels and the ADC, the offset cancellation may not achieve its desired effect. Therefore, reliable operation of the battery may not be guaranteed.